SNAP-Vista® Green is a green fluorescent substrate that can be used to label SNAP-tag® fusion proteins (in cell lysates or purified proteins) for detection by SDS-PAGE. This substrate (BG-Vista Green) is based on fluorescein and is optimized for excitation with the 488 nm laser excitation line in a laser based gel scanner. It can also be excited using 360 nm light from a standard UV-transilluminator. It has an excitation maximum at 500 nm and emission maxima at 524 nm. This package includes 50 nmol of SNAP-Vista Green substrate, sufficient to label one hundred 20 µl samples containing SNAP-tag fusion protein for in-gel detection.
The SNAP-tag protein labeling system enables the specific, covalent attachment of virtually any molecule to a protein of interest. The SNAP-tag is a protein based on human O6-alkylguanine-DNA alkyltransferase (hAGT). SNAP-tag substrates are fluorophores, biotin or beads conjugated to guanine or chloropyrimidine leaving groups via a benzyl linker. In the labeling reaction, the substituted benzyl group of the substrate is covalently attached to the SNAP-tag.
There are two steps to using this system: subcloning and expression of the protein of interest as a SNAP-tag fusion, and labeling of the fusion with the SNAP-tag substrate of choice. Expression of SNAP-tag fusion proteins is described in the documentation supplied with SNAP-tag plasmids. The labeling of the fusion proteins with the SNAP-tag substrate for detection by SDS-PAGE is described in this document.